Re: [PATCH 15/21] mm: memmap_init: iterate over memblock regions rather that check each PFN
From: Qian Cai <hidden>
Date: 2020-04-20 14:26:14
Also in:
linux-alpha, linux-arch, linux-mm, linux-riscv, linux-um
Subsystem:
memory management, memory management - page allocator, the rest · Maintainers:
Andrew Morton, Vlastimil Babka, Linus Torvalds
quoted hunk ↗ jump to hunk
On Apr 12, 2020, at 3:48 PM, Mike Rapoport [off-list ref] wrote: From: Baoquan He <redacted> When called during boot the memmap_init_zone() function checks if each PFN is valid and actually belongs to the node being initialized using early_pfn_valid() and early_pfn_in_nid(). Each such check may cost up to O(log(n)) where n is the number of memory banks, so for large amount of memory overall time spent in early_pfn*() becomes substantial. Since the information is anyway present in memblock, we can iterate over memblock memory regions in memmap_init() and only call memmap_init_zone() for PFN ranges that are know to be valid and in the appropriate node. Signed-off-by: Baoquan He <redacted> Signed-off-by: Mike Rapoport <redacted> --- mm/page_alloc.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7f6a3081edb8..c43ce8709457 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c@@ -5995,14 +5995,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,* function. They do not exist on hotplugged memory. */ if (context == MEMMAP_EARLY) { - if (!early_pfn_valid(pfn)) { - pfn = next_pfn(pfn); - continue; - } - if (!early_pfn_in_nid(pfn, nid)) { - pfn++; - continue; - }
This causes a compilation warning from Clang, mm/page_alloc.c:5917:39: warning: unused function 'next_pfn' [-Wunused-function] static inline __meminit unsigned long next_pfn(unsigned long pfn) This should fix it,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d469384c9ca7..b48336e20bdc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c@@ -5912,23 +5912,6 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn) return false; } -#ifdef CONFIG_SPARSEMEM -/* Skip PFNs that belong to non-present sections */ -static inline __meminit unsigned long next_pfn(unsigned long pfn) -{ - const unsigned long section_nr = pfn_to_section_nr(++pfn); - - if (present_section_nr(section_nr)) - return pfn; - return section_nr_to_pfn(next_present_section_nr(section_nr)); -} -#else -static inline __meminit unsigned long next_pfn(unsigned long pfn) -{ - return pfn++; -} -#endif - /* * Initially all pages are reserved - free ones are freed * up by memblock_free_all() once the early boot process is
quoted hunk ↗ jump to hunk
if (overlap_memmap_init(zone, &pfn)) continue; if (defer_init(nid, pfn, end_pfn))@@ -6118,9 +6110,23 @@ static void __meminit zone_init_free_lists(struct zone *zone)} void __meminit __weak memmap_init(unsigned long size, int nid, - unsigned long zone, unsigned long start_pfn) + unsigned long zone, + unsigned long range_start_pfn) { - memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL); + unsigned long start_pfn, end_pfn; + unsigned long range_end_pfn = range_start_pfn + size; + int i; + + for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) { + start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn); + end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn); + + if (end_pfn > start_pfn) { + size = end_pfn - start_pfn; + memmap_init_zone(size, nid, zone, start_pfn, + MEMMAP_EARLY, NULL); + } + } } static int zone_batchsize(struct zone *zone) -- 2.25.1